The positioning of a patient table will be explained below using the example of a radiological examination; however, it is equally required for the use of other medical installations. For the planning of a radiological examination, for example, using computed tomography, a topogram of the area under examination is established. The topogram is the basis of the anatomical planning for the subsequent diagnostic scan. Furthermore, various parameters for automated optimization of an examination log may be derived from the topogram.
Positioning of an image capture area (also referred to as scan area) may at present take place by manual selection of a start line and an end line of the image capture area marked by a light beam localizer with laser marking lines on a patient or examination subject who or that is lying on a patient table of the installation movable in the longitudinal direction (e.g., z direction) relative to a scanner (e.g., the gantry of a CT scanner). The longitudinal axis of the patient may be parallel to the longitudinal direction of the patient table, and the patient table may be located outside the scanner. The start line and end line in this case extend in the width direction (e.g., x direction) of the patient table, as a result of which the image capture area is defined in the longitudinal direction of the patient.
In order to produce the topogram, the patient assumes a suitable position on the patient table. The operating personnel moves the table using driver commands into a suitable start position in order to capture an image of the organ or body region under examination. The start position is reached when the desired anatomical start point comes into alignment with a laser line in the gantry. In this case, the laser line marks the plane in which the scan begins.
It is known to compensate for positioning that is still imprecise at the beginning by manual readjustment by horizontal table movements. In this case, the operating personnel visually monitors, using a laser light beam localizer, whether the desired position in the scan plane has been reached.
DE 10 2007 017 794 B3 discloses an apparatus for the automated positioning of a patient table relative to a medical installation, which apparatus has a display and operating unit designed for outputting a patient image. The apparatus is designed for defining at least one item of reference location information on the patient table whilst simultaneously representing the item of reference location information in the patient image, as well as for subsequently moving the patient table with the aid of a positioning system, wherein the item of reference location information is brought into alignment with an image capture area of the medical installation.